It could be a dead battery, and a faulty power supply. You can test your power supply to make sure it's good, also make sure your battery is charged. You're going to have to start eliminating things to get down to the problem. I first thought it could be the MX-4 causing a short. Though after reading on their website it looks like it doesn't contain any metal so it's not conductive.

You could also try to inspect those ribbon cables. I recently bought 2 more rog laptops on ebay (g53jw and g46vw) and both had bad ribbon cables. The G46's cable was so bad it was missing 2 points so I had to replace it, the g53's was shorted so if you pushed the backlit key it would change the video preset. I ended up fixing it by removing a very small part of the cable at the end.

It might be best to take everything apart and do a simple test with just the motherboard assembly, usb keyboard and a vga monitor. That's where I would start if I were you. If you get it working again add another piece of hardware like the ssd and keep going until you find the culprit. Also remember that connections in a laptop are delicate and you should never use force. I'm not saying that you did, It's just a friendly reminder.

Good luck with everything, let us know what you find.